Snow falls and accumulates in many places during the winter months and accumulated snow must be removed from roads, parking lots, driveways, etc., to allow vehicles to safely pass. There are a great number of methods for removing snow, but the most common method is to use a vehicle mounted plow. The most common type of plow is an angled blade plow, which may be moved to channel snow from an area in front of the plow vehicle to an area along the outer edge of the road, street or, in the case of a parking lot, to areas where the snow can be piled away from the parking surface.
Effective and efficient snow plowing requires considerable effort. During the plowing operation, a plow blade may be operated in a straight mode, in which the plow is substantially perpendicular to a direction of travel of the vehicle, or at an angled move, in which the plow is angled left or right relative the direction of travel. In both these position, snow will slough off at least one end of the blade. In the case of the straight mode, it will slough off both ends, which is not desirable. In the angled mode it will slough off the leading end, which is also not desirable. In both positions the ridge or ridges of snow will need to be removed by going over the plowed area a second time or even a third time depending on the depth of the snow. These extra passes double or even triple the time required to do a neat job. Therefore, there is a need for a plow and/or an attachment for existing plows, that will eliminate the need to perform these extra passes and, consequently, decreasing the plow time per job.
There have been a number of attempts to address this problem. Historically, these efforts have involved the addition of structures on each end of the snowplow blade. These structures are generally effective at preventing the sloughing of snow from the ends of the blade when the blade is positioned the straight mode. However, they hinder the operation of the plow when it is used in an angled mode, as the snow cannot easily slide off of the plow blade to form a snow bank Rather, snow is trapped in the area between the blade and the structure and plowed snow must move across the trapped snow to the snow bank. Because the plowed snow tends to stick to the trapped snow, this results in uneven snow banks. Further, because the structure interferes with the compression of the snow bank, it is common for large loose clumps of snow that are not compressed into the snow bank to roll into the roadway. Therefore, there is a need for a plow and/or an attachment for existing plows, which will prevent the sloughing of snow from the blade but will not hinder operation of the plow when it is used in an angled mode.
At least two patents have recognized the problem of preventing the sloughing of snow from the plow blade without hindering operation of the plow when it is used in an angled mode and each have disclosed inventions that purport to overcome it. Each patent is said to accomplish this by including a selectively extendable barrier attachment that may be retracted when the plow is used in an angled mode. Unfortunately, each has significant drawbacks that have prevented either invention from be placed in widespread commercial use.
The first such patent is U.S. Pat. No. 5,903,986, titled “Snow plow with side gate”. This patent is directed to a snowplow blade that includes a forward extending gate to catch snow rolling off the snowplow blade. The gate follows a trajectory forward from the curb edge of the plow blade and is said to prevent catching the extension gate with the curb regardless of angulations of the plow blade or the degree of extension. The extension gate extension mechanism may be completely attached to the rear surface of the plow blade to operate independently of angulation of the plow blade.
This patent would appear to succeed at preventing the sloughing of snow from the plow blade without hindering operation of the plow when it is used in an angled mode. However, this will only work for so long as it remains undamaged, and nature of the design makes such damage inevitable. For example, the fixed design of the gate makes it extremely vulnerable to damage when plowing over rough dirt roads, uneven concrete, or asphalt having frost heaves, uneven joints or extending manholes. Further, when plowing parking lots and driveways, it is common to not have enough space to push the snow against existing piles and, therefore, the operator needs to push the piles backward. Unfortunately, existing piles tend to thaw and then refreeze between storms, which puts a great amount of stress on the blade, and attachment, when performing this task. Even in the pulled back position, the side gate of U.S. Pat. No. 5,903,986 cannot withstand the stresses imposed on it under these circumstances. In addition to the risk of damage to the gate, the use of a gate that retracts toward the vehicle either requires the plow to be mounted further in front of the vehicle than is normal or a limitation on the amount of angling of the plow in order to avoid damage to the vehicle. Finally, this device cannot be easily mounted to existing plows, as it requires multiple welds and/or drilling and bolting. Therefore, there is a need for a plow and/or plow attachment that is not prone to damage through normal use, does not requires the plow to be mounted further in front of the vehicle than is normal, does not limit the amount of angling of the plow in order to avoid damage to the vehicle and it relatively easy to attach to existing plows.
The second patent that includes a retractable barrier attachment is U.S. Pat. No. 6,681,505, titled “Snow plow barrier attachment”. This patent is directed to a snowplow blade that includes a selectively extendable barrier attachment. The barrier attachment includes a base pivotally secured to the plow blade and secured to one end of each of a number of flexible members that are also engaged by a retraction mechanism for the barrier attachment that is disposed on the blade. The retraction mechanism is used to automatically retract and extend the flexible members as the base is pivoted between a retracted position and a deployed position on the blade. In the deployed position, the flexible members form a wall that prevents snow collected or diverted by the plow blade from passing through the barrier attachment.
This patent would appear to succeed at preventing the sloughing of snow from the plow blade without hindering operation of the plow when it is used in an angled mode, and likewise does not require that the plow be mounted in an extended position or that the angle of the blade be limited. However this attachment is even more prone to damage than the gate disclosed in U.S. Pat. No. 5,903,986. For example, the arm that forms the base of the gate is a relatively thin metal bar that is very easy to damage and would not withstand being jammed into a bank of icy snow when it is extended. Accordingly, to protect the base, the user would need to raise the barriers before reaching the snow pile, which would greatly defeat the purpose of the gate. Further, in dumping a full load of snow at the end of a plow run, it is often necessary to turn the vehicle while the plow remains in straight mode. This turning would cause the snow to be forced against the flexible sides, causing them to collapse. Further, like the gate of U.S. Pat. No. 5,903,986, this barrier is not easily mounted to existing plows.
Therefore, there is a need for a plow and/or an attachment for existing plows, which will prevent the sloughing of snow from the blade, will not hinder operation of the plow when it is used in an angled mode, is not prone to damage through normal use, does not require the plow to be mounted further in front of the vehicle than is normal, does not limit the amount of angling of the plow in order to avoid damage to the vehicle, and is relatively easy to attach to existing plows.